Make Parse return value-canonical Subject Identifier form#23
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Registry constructors return pointers so the codec can populate them
via UnmarshalJSON, but Parse previously leaked that pointer form. A
caller constructs identifiers as value literals (IssSubID{}) yet read
them back as *IssSubID, so a direct type assertion silently took the
!ok branch on whichever form it did not expect.
Normalize Parse to the value form: a reflection-based deref dereferences
the populated pointer before returning, applied to the built-ins, the
UnknownFormat carrier, and every nested aliases element. deref falls
back to the original pointer for an extension type registered with
pointer-receiver methods rather than panicking. Parse and the
SubjectIdentifier interface godoc now document the canonical value form
and the extension-type value-receiver constraint.
Also make AliasesID.Validate detect nesting by the format discriminator
(Format() == "aliases") instead of a value type assertion. The old
check missed a nested aliases identifier arriving from the wire, which
Parse populates in pointer form, so ErrNestedAliases silently failed to
fire on real input; a hand-built value-form nested alias was still
caught. Switch the OpaqueID and UnknownFormat compile-time assertions
to value form to match the other built-ins.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Record the initial 0.1.0 API surface and the 0.2.0 value-canonical Parse change, replacing the stale pre-release "no public API yet" note. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
Parsenow returns the value form of a Subject Identifier (subjectid.IssSubID, never*IssSubID), so the dynamic type a caller reads back fromParseis identical to the struct literal they construct by hand.Why
Registry constructors return pointers (
&IssSubID{}) so the codec can populate them viaUnmarshalJSON, butParseleaked that pointer form. Since every behavior method has a value receiver, a caller naturally buildsIssSubID{}but read back*IssSubID— a direct type assertion silently took the!okbranch on whichever form it didn't expect. The library's API now commits to one canonical dynamic form.This is settled before the first
v0.1.0tag, so there is no released contract to break.Changes
unmarshal.go— new reflectionderefhelper;Parsereturns value form for built-ins, theUnknownFormatcarrier, and nested aliases elements.dereffalls back to the original pointer for a pointer-receiver extension type instead of panicking.aliases.go— nested-aliases detection now usesFormat() == "aliases"instead of a value type assertion. This fixes a latent bug: a nested aliases identifier arriving from the wire (pointer form) previously escapedErrNestedAliases, while a hand-built value-form one was caught. New testTestParseNestedAliasesFromWireRejectedcovers it.subjectid.go/registry.go— godoc documents the canonical value form and the extension-type value-receiver constraint.opaque.go/unknown.go— compile-time assertions switched to value form, matching the other six built-ins, so a future pointer-receiver regression fails to compile.canonical_form_test.go.Verification
gofmtclean ·go vetclean ·golangci-lint0 issues ·go test -race ./...green.🤖 Generated with Claude Code